I can’t access my Proton Mail without my 2FA, additionally I can’t even access my 2FA without my email address (verification code is sent to my mail to unlock my 2FA codes + I need the master password). If i lose one of them I am screwed you would say, but it’s not the case.
What I did is to write down my Proton Mail Password and its secret code for 2FA + My Ente Authentication credentials (mail + master password). This way I will always be able to access my Proton Mail, even if i lose access to my 2FA app.
This is the worst case scenario, i also have a second phone where i keep Proton Pass and 2FA logged in, so if I lose my main phone, I am not completely locked out.